The invention relates to a shielded housing for use in various high frequency electromagnetic applications, e.g. a shielded housing for a strip line or microstrip transmission device, a waveguide or some other device with a housing which constitutes the RF ground. The housing is of the kind substantially consisting of an electrically conducting material and having a top wall, a bottom wall and two side walls serving as a ground plane, at least for RF frequencies, said housing comprising an upper part and a lower part being fitted together, and possibly further parts, such as end walls or the like.
It is commonplace to form a housing of two parts, such as a unitary box-like lower part with bottom and side walls, and a top wall in the form of a lid. Sometimes the lid is fitted into a seat in the form of recesses in the upper portions of the side walls, or the lid is provided with a downwardly extending flange. In any case, it is often a problem to assemble the two parts in such a way that a good direct DC connection or a well-defined capacitive coupling is obtained between the two parts, without causing inter-modulation products or other disturbing effects. Conventional methods of joining the two parts are soldering or mechanically joining the two part by a plurality of fasteners, such as rivets or screws. These methods are generally cumbersome and expensive.
The main object of the present invention is to provide a shielded housing which can be assembled easily and at low cost while securing a well-defined coupling between the two parts.
This object is achieved for a shielded housing having the features defined in claim 1. Accordingly, an upper part with two side flanges is fitted together with a lower part likewise having two side flanges in such a way that the two pairs of side flanges resiliently make a surface contact with each other. In this way, a well-defined coupling is secured.
Preferably, the two parts are made of a metallic material coated with an electrically insulating material, e.g. aluminium with an oxide layer formed in an anodising process.
These and other advantageous features are stated in the dependent claims and will be apparent from the description below.
The invention will be explained more fully below with reference to the drawings illustrating a preferred embodiment.